The blockchain concept can be enormously useful in a relatively narrow range of applications. Improvements on the Bitcoin blockchain may resolve some of that technology’s inherent problems with scalability and ecological footprint. In that case, such a version might plausibly even provide a viable backbone for a wholly new derivative of Bitcoin. It will certainly enable wide adoption of the technology for securely recording property transfers of all sorts—land, stocks, intellectual property, etc.
Currently there are a large number of ventures which seek to capitalize on the power of blockchains. Have any been yet successful? Perhaps so but only as an attraction for venture capital.
Optimistically, a radically better way will be found to provide crypto level security across a globally networked ledger with some untrustworthy participants. Bitcoin blockchain has shown the way. If such a breakthrough happens, blockchain will realize its potential. Even so, I for one, have trouble imagining stashing more than one or two globally distributed databases on more than a few ( say 100,000) nodes across the internet. Scale limits the penetration of this technology. Not a time for blind optimism.